Connecting apparatus for a plurality of cyclone type furnaces in series



Oct. 5, 1965 YUKIO NOGlWA 3,210,061

CONNECTING APPARATUS FOR A PLURALITY 0F CYCLONE TYPE FURNACES IN SERIES Filed Feb. 2, 196].

IN VEN TOR.

United States Patent 3,210,061 CONNECTING APPARATUS FOR A PLURALITY 0F CYCLONE TYPE FURNACES IN SERIES Yukio Nogiwa, 121 l-chome Narimune, Suginami-ku, Tokyo, Japan Filed Feb. 2, 1961, Ser. No. 86,733 Claims priority, application Japan, Feb. 8, 1960, 35/ 3,508 4 Claims. (Cl. 266-24) The present invention relates to a connecting apparatus for plurality of cyclone type furnaces arranged in series.

An object of the present invention is to simplify a furnace apparatus, wherein a plurality of cyclone type furnaces are so arranged that gas passages of said furnaces may be mutually in series and wherein fine powders of ores, limestone, fuel and the like are treated. The invention relates to apparatus for dispensing with the mechanical apparatus usually provided at the discharge outlet of the bottom of a posterior cyclone type furnace, with respect to the gas-flowing direction, by providing a gas ejector at the outlet portion of the bottom of the posterior cyclone type furnace producing a continuous transportation of materials collected at the bottom of the posterior cyclone type furnace to an anterior cyclone type furnace.

Another object of the present invention is to obviate such defects as abrasion, burning and the like of the mechanical means at the discharge portion at the furnace bottom of cyclone type furnaces.

A further object of the present invention is to obviate the clogging of powdered materials collected at the furnace bottom of the cyclone type furnaces.

A still further object of the present invention is to make the operation of cyclone type furnaces uniform.

Other objects, features and advantages of the present invention will become apparent from the following description.

In cyclone type furnaces connected in series, the gas pressure within an anterior furnace, with respect to the gas-flowing direction, is considerably higher than that of a posterior furnace because of the decrease in gas pressure due to the cyclone action. As a result thereof, means must be provided that gas from the anterior furnace may not be blown into the bottom of an interconnected posterior furnace. Mechanical means as rotary valves and screw conveyors are usually used for feeding the pulverized powder collected at the bottom of the posterior furnace to the anterior furnace. However, since these valves and conveyors are exposed to extremely high temperatures in the case of iron manufacture, they are required to be made of refractory material, heat resistant material and the like. Nevertheless, they are often damaged by abrasion, burning and the like. Also powdered materials collected at the bottom of the furnace often clog so that the supply of raw materials is inevitably interrupted, and other difiiculties are liable to occur.

The present invention is intended to obviate those defects as described above and is characterized in that in the treatment of powdered raw materials such as iron ores, for examples, hematite, limonite and magnetite, limestone and the like in mutual arrangement in a series of a plurality of cyclone type furnaces, a furnace feed spout for gaseous fluid under pressure is so related to the discharge outlet of another cyclone type furnace that the ores or other additives to be treated are introduced into the anterior furnace by the ejector action created by the jet of fluid from the feed spout. Accordingly, in the apparatus of the present invention, mechanical valves, as used in known furnaces of this type, can be eliminated. Thus, the abrasion and burning of mechanical valves and clogging of charges do not occur.

3,Zl0,06 l Patented Oct. 5, 1965 In order that the invention may more readily be understood, reference is now made, by way of example, to the accompanying drawings in which:

FIGURE 1 is a cross-sectional elevation illustrating diagrammatically the connecting apparatus for cyclone type furnaces, according to the present invention, and

FIGURE 2 is a plan view of the same.

Referring to the drawings, 1, 2, 3 and 4 designate, respectively, a furnace I, furnace II, furnace III and furnace IV, all of which are of cyclone type. Furnace I is a melting furnace; furnace II is a gas regulating furnace; furnace III is a reduction furnace; and furnace IV is a preliminary reduction furnace. These furnaces I, II, III and IV are vertically arranged as illustrated in FIG. 1 that gas passages of said furnaces may be in series.

As an example, the manufacture of iron from hematite ore in accordance with the practice of the invention is explained in the following:

First, a hot gas blast is fed through a feed pipe 5. This pipe is provided at its front portion 6 with a convergently contracted cross-sectional area nozzle 7. The front end of the nozzle 7 opens into the rear end 9 of a divergent pipe 8 (i.e. with its diameter gradually increasing forward) for conveying carbon powder from the bottom 10 of the furnace II by means of the jet of hot blast injected from the jet orifice of said nozzle 7 and acts as a pneumatic ejector provided by the injection of said hot blast. The hot blast is tangentially blown into the furnace I. By so doing, the pressure of the hot blast is remarkably reduced in front of said nozzle I 7 and then is restored in the front end of the pipe 8 and thereafter the hot blast enters the furnace I. The fine powder of carbon and other carbonaceous material (hereinafter called carbon) preliminarily heated in furnace II are sucked into the vicinity of the jet orifice of the nozzle 7 through the convergent bottom 10 of the furnace II under a negative pressure and then conveyed by the hot blast into the furnace I. Said carbon combines in the furnace I with oxygen in the hot blast from the pipe 5 to produce CO gas in a large quantity an CO in a small quantity. The interior of the furnace I is then heated to an extremely high temperature, for instance, 1500 to 1700 C. due to the heat generation at that time. This temperature can be appropriately adjusted by the temperature of the hot blast and the ratio of the hot blast and carbon supplied.

Further, in this embodiment, when respective inner diameters of the feed pipe 5, the nozzle 7, the rear end 9 and the front end of the divergent pipe 8 and the convergent bottom 10 of the furnace II he mm., 25 mm., 35 mm., mm., and 35 mm. and the hot air of 800 C. was blown into the divergent pipe 8 at the rate of 55 kg./hour from the feed pipe 5, the pressures at said pipe 5, at said bottom 10 and at said front end of the divergent pipe 8 amounted respectively to 280 mm. aq., mm. aq. and mm. aq. Approximately 10% of gas in the furnace II and excessive fine powdered carbon therein were sucked into the rear end 9 by the ejector action and then forced into the furnace I while mixing with the hot blast from the pipe 5.

From a pipe 11 a suitable gas such as town gas is fed in said furnace I at a high speed. Said pipe 11 is formed with a convergent nozzle 12 at its front end. Said nozzle is opened to the rear end 14 of a divergent pipe 13 connected to the furnace I and it is also designed that the gas from said pipe 11 may be tangentially introduced into the furnace I through the pipe 13, and the hot gas fed in the furnace I from the divergent pipe 8 may be well mixed with said gas from the pipe 13. Thus, a negative pressure is generated at the rear end 14 to which said nozzle 12 is open and a gas-ejector action takes place therein. The finely divided sponge iron and CaO particles preliminarily heated and reduced in the furnace III are collected at the bottom of the furnace III and then drawn through the front end 17 of pipe 16 into the rear end 14 of the divergent pipe 13 and thereafter fed into the furnace I through pipe 13 by the ejector action due to the nozzle 12. Since the furnace I is at a high temperature as described before, said fine particles of sponge iron and CaO blown into the furnace I are melted immediately therein and gathered along the surrounding wall by the cyclonic action and collected at the furnace bottom after flowing down on the furnace wall. 18 and 19 designate respectively the slag formed and the molten metallic iron. A high temperature gas mixture of N CO and CO formed in the furnace I is withdrawn by a discharging pipe 20 of the furnace I, said gas being tangentially blown into furnace II through inlet pipe 21. The fine carbon powder 23 in coal reservoir 22 is continuously charged in the furnace II by feeder 24 through a charging pipe 25 and the fine carbon powder immediately reacts with CO in the gas within said furnace II to produce CO. Since the chemical reaction just referred to is the endothermic reaction, the temperature of the gas is consider ably decreased in the furnace II. However, when the temperature in the furnace II does not lower to the desired temperature, for instance 1000 to 1200 C. by the temperature decease due to this endothermic reaction, steam may be blown into the inlet of pipe 21 or into any other appropriate place to react with the fine carbon powder, thereby producing both CO gas and H gas. This reaction is also an endothermic reaction and accordingly, a further decrease in the temperature takes place. Thus, the desired temperature, for example, of 1000 to 1200 C. can be obtained. The temperature in the furnace III can be maintained at about 800 to 1000" C. through the me dium of the gas temperature in the furnace II. When the amount of carbon to be supplied through said feeder 24 is kept in an amount far greater than is required for the chemical reaction in the furnace II, the reaction residue is collected at the furnace bottom 10 by the cyclonic action and thereafter drawn into the rear end 9 from said bottom 10, by the gas stream from the pipe 5 and introduced through said pipe 8 into the furnace I. The majority of gas in furnace II is withdrawn from a discharge pipe 26, while a part thereof is drawn into the pipe 8 by the air ejector while entraining fine carbon powder as described before. Thereby, the collecting efficiency of the cyclonic action is extremely improved. The gas withdrawn through said discharge pipe 26 is contracted at a convergent nozzle 27 at the front end of said pipe 26, and thereafter enters the rear end 29 of a divergent pipe 28 and gradually expands and is blown tangentially into the furnace III through pipe 28. The action of this convergent nozzle 27 is the same as that of the nozzle 7 described before, and a gas ejector actiontakes place due to a negative pressure generated by the action of nozzle 27, and the FeO powder and limestone powder supplied from the bottom 30 of the furnace IV are carried by the gas stream from the furnace II and enter the furnace III. FeO is reduced in the furnace III to produce sponge iron particles, and the limestone powder is decomposed into CO gas and CaO powder. The Fe and CaO in the powdered form are gathered by the cyclonic action and collected at the furnace bottom 15 and thereafter are drawn into the rear end 14 of the pipe 13 through the pipe 16 and its front end 17, while being carried by the gas stream from the pipe 11 as described before.

The temperature in the furnace III is preferably maintained as high as possible in order to rapidly accelerate the reduction, but if it be too high, the sponge iron particles formed cohere with each other. Therefore, an appropriate temperature such as 800 to 1000 C. should be chosen. The adjustment of this temperature can be accomplished by controlling the temperature in the furnace II at 1000 to 1200 C. The gas in the furnace III is a gas mixture of N CO and CO This gas is withdrawn through a discharge pipe 31 and blown into the furnace IV in the tangential direction through a pipe 32 at the front end of pipe 31. A mixture 34 of the finely powdered iron ore and finely divided limestone in the ore reservoir 33 is continuously fed into pipe 32 from a charging pipe 36 through a feeder 35. Said fine pulverized iron ore is preliminarily reduced in the furnace IV to FeO powder and is collected with limestone powder by the cyclonic action and mixed up. Thereafter, the mixture falls directly in front of the nozzle 27 at the front end of pipe 26, and conveyed by the gas stream from furnace II under a negative pressure generated by the ejector action of nozzle 27 and enters th furnace III through the pipe 28. The temperature in the furnace IV ranges from about 500 to 700 C., and the majority of gas is withdrawn through a discharge pipe 37. A part of the gas in the furnace 1V is drawn in by the ejector action of nozzle 27 and falls within the rear end 29 of pipe 28 from the furnace bottom 30, thereby the collecting efficiency of the cyclonic action is remarkably improved.

Thus, according to the connecting apparatus of the present invention, there are no moving mechanical parts, for example, rotating parts and the like, and all of the mechanism consists of stationary parts. There are, likewise, no closed portions, and the valve action is actuated only by the gas flowing through the Venturi type ejectors. Thus, the object of required treatment as well as refining can be accomplished without any stagnation of the powdered materials. The connecting apparatus according to the present invention can bring about an extremely large increase in the efficiency of furnace operation.

In the above embodiment when the respective inner diameters of the pipe 11, the nozzle 12, the rear end 14, the pipe 13 and the front end 17 of the pipe 16 are 20 mm., 2 mm., 11 mm., 24 mm. and 25 mm. and the town gas at 20 C. and under pressure of 2 atmospheres was supplied at the rate of 7 kg./hour from the pipe 11, the pressures at the front end 17 and the pipe 13 amounted to 20 mm. aq. and 195 mm. aq., respectively. Approximately 10% of the gas in the furnace III, Fe powder and CaO powder were drawn into the rear end 1 of pipe 13 by the ejector action and then blown into the furnace I through the pipe 13, and admixed with the gas such as town gas from the pipe 11.

Moreover, when the respective inner diameters of the pipe 26, the nozzle 27, the rear end 29, the divergent pipe 28 and the discharging bottom 30 are mm., 30 mm., 40 mm., 70 mm. and 35 mm. and the gas mixture of N and CO at 1100 C. was supplied at the rate of kg./ hour from the pipe 26, the pressures at the pipe 26, the bottom 30 and the divergent pipe 28 amounted to mm. aq., 5 mm. aq. and 50 mm. aq., respectively. Approximately 10% of the gas in the furnace IV, FeO powder and limestone powder were drawn into the rear end 29 and blown into the furnace III, and admixed with the gas from the pipe 26.

As will be apparent from the above description, when the smelting is carried out in such an arrangement of cyclone furnaces by effectively utilizing the ejector action, the ore can be uniformly circulated by the gas stream without any stagnation, and in addition, since the raw material iron ore is fine powder and can quickly be reduced and melted, the manufacture of iron can be efficiently carried out. On the other hand, the amount of carbon to be supplied by the feeder 24 can be retained in an amount required for the reaction in furnace II or slightly in excess of said, amount, and the amount of carbon required in furnace I can be supplied to the furnace I by directly feeding the carbon 39 in the reservoir 38 from the feed pipe 41 through the feeder 40. The fine pulverized Fe and CaO to be conveyed by the gas stream through pipe 16 may, by increasing the suction force of the nozzle 7, be directly fed in the rear end 9 of the pipe 8 through a pipe 42 formed by extending pipe 16. Thus,

when it is preferable to dispense with said pipe system including the pipe 11, it is possible to design to that effect.

The above-mentioned iron making method is shown only by way of example. The present invention is in no way limited to the process for manufacturing iron. The present invention can also be applied to the chemical treatment such as heating, melting, reducing, or oxidation of pulverized ore or cement raw material when a chemical reaction is to be carried out by using a plurality of cyclone furnaces in series. As a fuel, other solid fuel, liquid fuel and gaseous fuel can also be used for the above-mentioned treatment as with pulverized coal as described before. The gas to be supplied to pipe 11 may be air, oxygen or hydrogen in place of the town gas in compliance with the treatment, and further, the discharged gas can sometimes be used effectively in circulation. Furthermore, the pressure and temperature of gas as well as shapes, sizes and arrangement of each ejector may be appropriately selected according to the design.

In the above-mentioned illustration regarding the drawings, the vertical arrangement of all cyclone type furnaces has been described. However, the horizontal arrangement of each furnace may also be possible by appropriately directing the furnace interconnecting pipes and by strengthening the negative pressure to be generated by the ejectors or using an additional blower. In order to obtain an effective mixing of gas with solid powder or liquid fuel supplied through the feeders 24, 35 and 40, the processes have already been suggested wherein these materials are scattered by blowing a high pressure gas against them. Such processes are being used in the various fields of industry, this process may be, of course, applied to the apparatus of the present invention.

What I claim is:

1. In a furnace apparatus, in combination, a plurality of cyclone furnaces, each furnace having a tangentially related treating gas inlet conduit and a collection outlet, a gas outlet conduit centrally associated with each of said furnaces for removing gas therefrom, one of said furnaces constituting the final treatment furnace and another furnace constituting the initial treatment furnace, at least one furnace interposed between said final and initial treatment furnaces, said furnaces being connected in series whereby the gas outlet conduit of one furnace communicates with the gas inlet conduit of the adjacent furnace, means introducing a treating gas into the gas inlet conduit of said final treatment furnace, the gas pressure within said furnaces sequentially decreasing in the direction of the gas flow through the series of furnaces, and a Venturi located within the inlet conduit of at least one of said furnaces whereby the gas flow therethrough produces a low pressure area within said inlet conduit and means establishing direct communication between said low pressure area and the collection outlet of a subsequent furnace with respect to the gas flow, the pressure at said low pressure area being less than the pressure within said subsequent furnace collection outlet.

2. In a furnace apparatus for processing ore comprising, in combination, a plurailty of cyclone furnaces each having a tangential gas inlet conduit and a centrally located gas outlet conduit and a collection outlet associated therewith, one of said furnaces constituting a melting furnace and another furnace constituting a reduction furnace, means supplying ore to said reduction furnace, said furnaces being connected in series whereby the outlet conduit of one furnace communicates with the inlet conduit of the adjacent furnace, means supplying pressurized hot gas to the inlet conduit of said melting furnace, a Venturi pump operated by pressurized gas having a low pressure inlet directly communicating with the collection outlet of the reducing furnace and an outlet in direct communication with the melting furnace whereby the material treated and collected in the reduction furnace will be injected into the melting furnace.

3. In a furnace apparatus as in claim 2, wherein said apparatus includes a gas regulating furnace and a preliminary reduction furnace constituting the means supplying ore to said reduction furnace, the inlet conduit of said gas regulating furnace communicating with the outlet conduit of said melting furnace, the outlet conduit of said gas regulating furnace communicating with the inlet of the said reduction furnace and the outlet conduit of said inlet of the said reduction furnace and the outlet conduit reduction furnace communicating with the inlet conduit of said preliminary reduction furnace, a Venturi within said melting furnace inlet conduit having a low pressure inlet directly communicating with the, collection outlet of said gas regulating furnace and a Venturi within the inlet conduit of said reduction furnace having a low pressure inlet directly communicating with the collection outlet of said preliminary reduction furnace.

4. In a furnace apparatus including first and sec-0nd cyclone-type furnaces each having an inlet and an outlet gas conduit, the outlet conduit of said first furnace communicating with the inlet conduit of said second furnace, said second furnace having a collection outlet directly communicating with the inlet conduit of said first furnace, means supplying pressurized gas into said inlet conduit of said first furnace, a connecting apparatus between said collection outlet and the associated inlet conduit comprising, in combination, a nozzle within the inlet conduit of said first furnace of restricted cross section increasing the gas velocity therethrough, the collection outlet of said second furnace directly communicating with said first furnace inlet conduit at a low pressure location adjacent said nozzle whereby material within said second furnace collecting at said collection outlet will be directly drawn from said second furnace into said first furnace inlet conduit.

References Cited by the Examiner UNITED STATES PATENTS 729,008 5/03 Sutton et al -9 XR 1,305,726 6/19 Leonard et al. 266-23 2,756,981 7/56 Muller 263-32 2,785,886 3/57 Muller 263-32 2,797,076 6/57 Muller 263-32 2,797,077 6/57 Muller 263-32 2,973,260 2/61 Nogiwa 266-24 3,010,766 11/61 Coski 302-51 FOREIGN PATENTS 198,525 7/58 Austria.

524,426 4/ 55 Italy.

788,826 1/58 Great Britain.

MORRIS O. WOLK, Primary Examiner.

RAY K. WINDHAM, Examiner. 

2. IN A FURNACE APPARATUS FOR PROCESSING ORE COMPRISING, IN COMBINATION, A PLURALITY OF CYCLONE FURNACES EACH HAVING A TANGENTIAL GAS INLET CONDUIT AND A CENTRALLY LOCATED GAS OUTLET CONDUIT AND A COLLECTION OUTLET ASSOCIATED THEREWITH, ONE OF SAID FURNACES CONSTITUTING A MELTING FURNACE AND ANOTHER FURNACE CONSTITUTING A REDUCTION FURNACE, MEANS SUPPLYING ORE TO SAID REDUCTION FURNACE, SAID FURNACES BEING CONNECTED TO SERIES WHEREBY THE OUTLT CONDUIT OF ONE FURNACE COMMUNICATES WITH THE INLET CONDUIT OF THE ADJACENT FURNACE, MEANS SUPPLYING PRESSURIZED HOT GAS TO THE INLET CONDUIT OF SAID MELTING FURNACE, A VENTURI PUMP OPERATED BY PRESSURIZED GAS HAVING A LOW PRESSURE INLET DIRECTLY COMMUNICATING WITH THE COLLECTION OUTLET OF 